WITH ISTOTES ON OTHER SPECIES. 



139 



served. In the basal part of the branch there are formed, in a single row, several 

 globular protoplasmic masses with distinct walls. The spaces around the individual 

 si)heres seem to be separated by faint false walls of protoplasmic substance, proba- 

 bly formed from the protoplasm of the segment. These spheres produce structures 

 which can be compared to nothing but germ tubes in their appearacne and growth ; 

 and I have seen them in all stages from the beginning of their formation to the length 

 shown in Fig. 121. They ordinarily grow towards the oogonium, but I have seen 

 two of them, developed from two spheres contained in the same segment, directed 

 away from it. In this last case they were in the lower segment of a branch of two 

 segments whose upper member showed the same condition as that drawn in Fig. 120. 

 While one's first inclination may be to regard these peculiar structures as specialized 

 male cells which produce fertilization tubes of a different type from those of the 

 Saprolegiiiece, yet the emptying of the apical parts of some branches, even of the 

 same ones that contain the spheres, and the fact of the growth of their tubes away 

 from the oogonium in one observed case, make it quite as probable that they are para- 

 sites in the antheridial branches. Yet if they are parasites, it is remarkable that they 

 should not have been seen in other parts of the plant. I have not been able to 

 observe what follows the contact of their tubes with the oogonium, not having seen 

 them late enough in their history. 



The general incompleteness of these observations, which bring up many interest- 

 ing possibilities, can justify nothing more than the suggestion of some of these 

 possibilities. The emptying of the separated apical parts of some branches without 

 any evident formation of fertilization tubes needs further investigation ; it is not 

 impossible that this species may be shown to differ from the Sajjrolegm'ece which have 

 been studied, in the occurrence of a truly sexual process. It is greatly to be hoped 

 that some one may soon have the opportunity of studying abundant material of this 

 plant. 



